Immi and Esme Fear, aged 10 and seven respectively, were caught by their red-faced mum Laura selling her bras and pants for 50p each outside their old house in Taunton, Somerset.
The family were selling their house at the time and needed to raise funds for the move to West Yorkshire.
So the troublesome twosome hatched their fundraising formula by raiding mum’s knicker drawer and trying to flog the contents.
It is unclear how many were sold or who the clientele was.
And after mum Laura took a photo of the pair during their elasticated adventure, it was recognised with an award in a competition by Jammie Dodgers biscuit manufacturer, Burton’s Biscuits.
Called ‘Sweet at Heart’, they asked parents to share snaps of their kids getting up to hilarious mischief.
And Jammie Dodgers awarding the hilarious photo first place, winning Laura’s family a Center Parcs stay.
Laura said: “I discovered the girls getting up to mischief, when I heard laughter through the open window.
“I was taping up boxes, ready to move house and the girls had taken it upon themselves to go into my bedroom and swipe some underwear.
“My initial thoughts were laughter and to grab my mobile phone and take a photo.
“I looked out of the window and saw both girls wearing pants on their heads.
“When I asked Immi and Esme why they decided to sell my bras they simply said, ‘because you said you had too many clothes to pack’.
“Immi and Esme are delighted to be selected as the winner.
“They think they are famous now and are so excited to have won a holiday for us all.”
Kate Needham, spokesman for Burton’s Biscuits, said: “We felt Laura’s photo of was a deserving competition winner.
“It really captured those moments all parents can resonate with, when they forgive their kids’ naughtiness because underneath, they know they have good intentions - or as we say - they’re ‘Sweet at Heart’.”